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(NohM'odeI.)

G. B.- MAYNADIER.

' ATTRITION MILL. No. 292,888. Patented Jan. 22. 1884.

' @M ULDIHIMIJ I Er'V Cn UNITED STATES PATENT OEEICE.

GUSTAVUS B. MAYNADIER, OF BOSTON, MASSACHUSETTS, ASSIGNOR OF ONEHALF TO WILLIAM H. OILLEY, OF SAME PLACE.

ATTRITION-MILL.

SPECIFICATION forming part of Letters Patent No. 292,338, dated January 2.?, 1884..V

Application led J une 14, 1883. (No model.)

,To all whom it may concern,.- I

Beit known that I, GUsrAvUs B.MAYNA DIER, of Boston, in the county of Suffolk and State of Massachusetts, have invented a new and useful Improvement in Attrition-Mills, of which the following is a specification.

My invention relates to improvements in attrition-mills in which the material is ground by the attrition and impact of portions of the material contained in revolving chambered heads against another portion contained in a hopper or case communicating with the chambers of the heads. l

The object of my invention is to provide means more effectual 'than any heretofore devised for keeping the hopper or case free from the dust or flour so largely produced in mills of this class. T'o attainI this object I have made the bottom of the hopper reticulated or sieve-like, and have` arranged the hopper or case so that it can be subjected .to a shaking or vibrating motion by means of suitable mechanism, substantially as hereinafter described.

In the accompanying drawings, which illustrate an attrition mill with its hopper. arranged to receive a shaking or vibratory motion and a device for imparting such motion to the hopper, Figure l is a front view, partly in section; and Fig. 2 is a cross-section on line 0c x of Fig. 3, which is a plan or top view.

The chambered heads A A are suitably mounted upon shafts, which are provided with pulleys 'a a', to be revolved in opposite directions, said heads having their open ends close against openings in the sides of the hopper B. The hopper B, instead of being iixed, as heretofore in such mills, is supported at one end by an arm, b, provided with journals or trunnions b', mounted in suitable boxes. The other end of the hopper B is supported by an arm, b, the outer extremity of whichrests on a toothed cam. C. An adjustable counter-weight, b, may be attached, as indicated in dotted lines, to regulate the weight thrown on the cam C. The cam C is provided with a shaft, c, and a pulley, c', by meansof which it can be revolved by a belt from one of the chambered heads or from any other suitable driving mechanism. In Fig-s. l and 3 the belt is shown as driven by the chambered head A.

By thus utilizing one of the heads a separate pulley-for driving the cam C is dispensed With. lThe teeth of the cam C are arranged to give the requisite motion to the outer extremity of the arm b2 to cause a shaking or tremor at that part of the hopper B opposite the open ends of the heads A A. The bottom of the hopper B is made like a screen or sieve, of any well-knownV construction, having its meshes oropenings of any desired size. In the drawings lI have shown the bottom made with perforations small on the 'inside and increasing in size to the outside.

Instead of making the bottom a part of the hopper, it can be made separate, so that lner or coarser sieves can be inserted at pleasure, or a new one be inserted to replace one too much worn. The bottom `may be made at orotherwise; but the preferred form is that shown in the drawings, that is concentric with the chamber-heads. This shape facilitates'the movement of the material next to the bottom and prevents the meshes of thevscreen from becoming clogged. The shaking or tremor caused by the revolving cam O and the jerking motion caused by having the bottom be low the center of the trunnions b keep the coarse material always on top and give a sliding or traveling motion to the finer material and dust next to the reticulated orsieve-like to receive a shaking or vibratory motion, andv means for imparting such motion, substantially as and for the purpose set forth.

G. B. MAYNADIER.

' Vitnesses WV. A. COPELAND, J. R. Snow. 

